Kleespies, M. (Corresponding author)FZJ*

1997
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Report No.: Juel-3487

Abstract: The elimination of fluoranthene in liquid cultures of Mycobacterium hodleri was clearly and only enhaneed by non toxie surfaetants. This answers the eontroversal question whether surfaetants ean improve bioavailability and bioelimination ofpolyeyclie aromatie hydroearbons (PARs). Four surfaetants (two Alkyl-Polyglueosides, Marlipal 013/90, and the zwitterionie surfaetant) were shown to be toxie for the Mycobacterium and inhibited fluoranthene elimination to different extents. By eontrast, solubilization of fluoranthene in aqueous solutions (up to 4 gIl) of the six nonionie surfaetants Tween 80, Marlipal 013/400, Genapol C200, Genapol 0200, Genapol T250, and Sapogenat T300 inereased elimination rates up to 2.5 fold as eompared to erystalline (non solubilized) fluoranthene. Inhibition of fluoranthene elimination by "preferential surfaetant utilization" (Tiehm, 1994) eould not be found. Strain EMI2 utilized 14C-fluoranthene (in eoneentrations down to 3.25 Ilgll) and the surfaetant Tween 80 (1 g/l) simultaneously. Elimination rates of erystalline fluoranthene were limited by mass transfer rates between fluoranthene particles and the aqueous phase whereas elimination rates of solubilized fluoranthene were limited by the mass transfer rates between the mieellar and aqueous pseudophases. Growth inhibition experiments gave no signifieant eorrelation between surfaetant toxieity and inhibition of fluoranthene elimination. However, deereases in respiration or enhaneed losses of potassium and other solutes eorrelated weIl with inhibitions of fluoranthene elimination. Based on these findings a eonduetivity test was developed. In eontrast to the toxie surfaetants the nontoxie ones either did not inerease or deereased medium eonduetivity. By eomparing toxicity data from literature with experimental data, surfaetant toxieity eould be eorrelated with the surfaetants' moleeular weights and their HLB-values: nonionie surfaetants with moleeular weights > 1000 seem to be nontoxie toMycobacteria irrespeetive of their HLBvalues whereas nonionie surfaetants with moleeular weights < 1000 and HLB-values < 15 were shown to be toxie to different strains of the genus Mycobacterium.

1. Institut für Chemie und Dynamik der Geosphäre (ICG)